Herbicidal compositions



Patented Dec. 1, 1953 HERBICIDAL COMPOSITIONS Arthur H. Schlesinger,Dayton, Ohio, assignor to Monsanto Chemical Company, St. Louis, Mo., a

corporation of Delaware No Drawing. Application August 23, 1952, SerialNo. 306,065

11 Claims.

The present invention provides new and highly valuable herbicidalcompositions and methods of destroying or preventing plant growth forwhich said compositions are employed.

I have found that improved and very efficient herbicidal compositionsare obtained when there are prepared oil-in-water emulsions of a ketoneselected from the class consisting of alkyl m-xenyl ketones and alkylp-xenyl ketones in which the alkyl radical has from 1 to 4 carbon atoms,or mixtures of such ketones. Examples of useful ketones for the presentpurpose are methyl m-xenyl ketone, methyl p-xenyl ketone, ethyl mxenylketone, ethyl p-xenyl ketone, isopropyl m-xenyl ketone, isopropylp-xenyl ketone, butyl m-xenyl ketone or isomeric mixtures of the same,e. g., a mixture of methyl m-xenyl ketone and methyl p-xenyl ketone. Thealkyl xenyl-ketones are readily obtainable, for example, by reaction ofbiphenyl with an acyl halide or an acid anhydride in the presence of aFriedel-Crafts type catalyst, by oxidation of an alkyl-substitutedbiphenyl, etc.

Herbicidal compositions containing the present alkyl xenyl ketones maybe readily obtained by first preparing a solution of the ketone in anorganic solvent and then adding the resulting solution to watercontaining an emulsifying agent to form an emulsion. Because of the veryhigh herbicidal efficiency of the alkyl m-xenyl ketones or the alkylp-xenyl ketones, they are present in the herbicidal compositions in onlyvery small concentrations, for example, in concentrations of from 0.1per cent to 2.0 per cent by weight of the total weight of the emulsion.Emulsifying agents which may be employed are those customarily used inthe art for the preparation of oil-in-water emulsions. The word oil" ishere used to designate any liquid which is insoluble in water. Ex-

amples of emulsifying agents which may be used includealkylbenzenesulfonates, long chained polyalkylene glycols, long-chainedsuccinates, etc. The emulsions may be used to destroy already existingplant growth by direct application to the undesirable plants, e. g., byspraying; or the emulsions may be employed to prevent plant growth byapplication to media which normally support plant growth. When employedto prevent plant growth, for example, in parking areas, highwayabutments, railway yards, etc., the emulsions may be applied by sprayingonly the surface of said media or they may be admixed with said media.Generally, spraying of only the soil surface is sufficient to preventplant growth in areas which are to be kept clear of plants. However, theemulsions may be incorporated into terials, e. a, soils, cinders, etc.

The oil-in-water emulsions of the present alkyl xeny1 ketones areparticularly valuable in that when applied to the leaves of broad-leafedplants they dry the leaves thereof. Application of some of the presentherbicidal compositions to such plants as cotton, beans, and peas causesleafdrying and thus permits more efiicient harvesting or hand-picking ofthe bolls or pods.

The present invention is further illustrated, but not limited, by thefollowing examples:

Example 1 Spray testing of the present herbicidal compositions wasconducted as follows:

Respective cyclohexanone solutions of methyl m-xenyl ketone and. ofmethyl p-xenyl ketone together with an emulsifying agent wererespectively added to water, the quantity of solution employed beingcalculated to give emulsions containing 6.3 per cent and 1.0 per cent ofthe methyl xenyl ketone, respectively, based on the total weight of eachemulsion. The quantity of emulsifying agent used was 0.2 per cent byweight, based on the total weight of each emulsion. Said emulsifyingagent comprised a mixture of a polyalkyleneglycol derivative and analkylbenzenesulfonate.

Three-week old corn and bean plants, respectively, were sprayed with theemulsions, two plants of each variety being employed. The spraying wascontinued until droplets formed on and/or fell from the foliage andstems of the sprayed plants, up to 15 ml. of the emulsion being appliedto each plant. The sprayed plants as well as two untreated blankspecimens of each plant were then allowed to remain under standardconditions of sunlight and watering for a period of one week. At the endof that time the sprayed plants were compared with the untreated Theinactivity otthe ortho-isomer, as shown above is remarkable. I

ketone per acre or to 50'lbs. per acre.

Example 2 Another method of testing for herbicidal efficiency of achemical involves noting the eiiects on seed germination and plantgrowth which may be evidenced byspraying soil surfaces. This test,commonly known as a lure-emergence test-was conducted as follows:

Boxes having a x 5" exposed area were partially filled with a layer ofsoil-and 20seeds were placed thereon and then covered with a' /g tolayer of soil which had been"screened to sieve. Test boxes containingseeds-each of rye grass, radish, cucumber and beet seeds, re-

spectively, were prepared. 'Iheisurfacesoil of. the

seeded boxes was then sprayed, respectively, with the 1.0 per cent andthe 0.3 per cent emulsions of m-methyl xenyl ketone of Example 1. Thequantity of each emulsion which was applied was calculated to correspondto either 20 lbs. of the In the present instance, 10.8 cc. of the0.3'per cent emul sion persquare inches of surface soil was calculatedto correspond to'20 'lbs. of the chemical per acre and 9.1 cc. of the1.0 per centemulsion to 50 lbs. of the-chemical per acre. 'The sprayedboxes as well as similarly seeded'but unsprayed boxes werethen'maintained at standard conditionso'f temperature and watering for aperiod of two weeks. At the endaofathat time the number ofhealthyseedlings in each box was counted. Thus the number ofnon-emerging and damaged seedlings was obtaine'dby difference. Thisdifierence is designated at"X.Per cent phytotoxicity" was determined'bythe ratioof X to the number of healthy seedlings in the .controls.

There was evidenced a 71-100 ,per cent phytotoxicity "to beets and'ryegrass at the 50 lbs. per

acre rate of 'a'pplicationand a 46 -70 per cent phytotoxicity toradishes and cucumbers at the same rate of application. At the 20 lbs.rate there was evidenced a phytotoxicity of "71-100 'per centagainst ryegrass and :beets, and a phytotoxicity of up to '46 per cent againstcuciim-- bers' and radishes.

'Errampled Operating asin'Example 2,-a commercial mixture of m-methyl'xenyl'ketone and 'p-methyl 'xenyl ketone (about 75% meta) was testedfor pie-emergence effects. The following seeds were 'used for thepre-emergence test: clover,'buck- "wheat, wild oats, beets, cheat grass,mustard,

rye-grass and morning glory. At the 50 lbs. per acre concentration(wherein'a 1.0'per'cent emulsion of the mixture of methyl m-xenyl"ketone and methyl p-xenyl ketone was used) there was evidenced a'71-'1'00per centphytotoxicity against clover, and-a 46-71 percent'phyto'toxicity against buckwheat, beets, cheat grass, "rye andmorning glory. The phytotoxi'city "against wild cats "at the sameconcentration was only up to 46 per cent.

While the .present alkyl xenyl-ketonesare most growth. The ketones mayalso be mixed with.

liquid or solid agricultural lpesticides, ve. g,

'secticides an'd'fungicides. "While solutions .of the present in saidemulsion in a quantity which is toxic to plant life.

2. A herbicidal composition comprising an oilin-water emulsion of analkyl m-xenyl ketone, said ketone being present in said emulsion in a:quantity which is toxic to plant .life.

3. A herbicidal composition comprising an oilin-water emulsion .ofm-methyl xenyl ketone, said ketone being present in said'emulsion in aquantity which is toxic to plant life.

4. A herbicidal composition comprising-an oilin-water emulsionofp-methyl xeny'l ketone, said ketone being present in said emulsion 'ina quantity which is toxic to plant life.

-5. The method of destroying undesirable plants which comprises applyingto said plants a toxic quantity of a herbicidal composition comprisingaketone selected from theclass .consistingof alkyl m-xenyl ketones andalkyl p-xenyl ketonesin which the alkyl radical has from 1-4 carbonatoms.

-6. The :method of preventing plant growth which comprises applying .tomedia normallysupporting said growth a herbicidal composition comprisinga-ketone selec'ted from the class consisting of alkyl m-xenyl ketonesand alkyl 1pxenyl ketones in which the alkyl radical has from l-4 carbonatoms.

7. The method of destroying undesirable plants which comprisesapplyingto said plants a toxic quantity of a herbicidal composition comprisingan oil-.in-water emulsion-of a .ketone selected from the classconsisting of alkyl m-xenyl 'ketones :and alkyl p-xenyl ketones in which.the

alkyl-radical has from 1-4 carbon atoms.

8. The method of destroying undesirable plants which comprises applyingto said plants a toxic quantity of a herbicidal composition-comprisingan oil-in-wateremulsion of an alkyl m-xenyllcetonein which thealkyl:radical has froml-icarbon atoms. A

9. The method of preventing plant .growth which comprises applying tosoils normally supporting said growth a herbicidal compositioncomprising an oil-in-water emulsion of a mixture of methyl :m-xenyl.ketone and methyl 1p- .xenyl :ketone.

.10. The :method of destroying undesirable 1131311138 which comprisesapplying :to said plants :a "toxic quantity of a herbicidal compositioncomprising :an cil-in-water emulsion 'of methyl -m xenyl ketone. 1

11. The method of destroying undesirable :plants which comprisesapplying to saidmla-nts a toxic quantity of a herbicidalcompositionfcomprising an oil-.in-water emulsions-of methyl pixenyl:ketone.

No references cited.

1. A HERBICIDAL COMPOSITION COMPRISING AN OILIN-WATER EMULSION OF AKETONE SELECTED FROM THE CLASS CONSISTING OF ALKYL M-XENYL KETONES ANDALKYL P-XENYL KETONES IN WHICH THE ALKYL RADICAL HAS FROM 1-4 CARBONATOMS, SAID KETONE BEING PRESENT IN SAID EMULSION IN A QUANTITY WHICH ISTOXIC TO PLANT LIFE.